1. Field of the Invention
The present invention relates to a turbine generator.
2. Description of the Related Art
There have been proposals in recent years that a turbine generator configured to generate power by use of exhaust heart from an internal combustion engine be mounted on vehicles and the like for the purpose of efficient use of the energy.
An apparatus in line with the proposals includes: a heat exchanger disposed upstream of a radiator; a pump configured to supply a liquid heating medium to the heat exchanger; a turbine generator configured to generate power by use of the heating medium evaporated by the heat exchanger; and a condenser configured to liquefy the gaseous heating medium discharged from the turbine generator, and to supply the liquefied heating medium to the pump. A coolant circulates between the internal combustion engine and the radiator for the purpose of cooling the internal combustion engine. The coolant cools the internal combustion engine, and thereafter the resultant high-temperature coolant is sent to the radiator. The heat exchanger exchanges the heat between the high-temperature coolant and the liquid heating medium supplied by the pump. This heat exchange evaporates the heating medium. The evaporated heating medium is supplied to a turbine in the turbine generator. The turbine is rotationally driven by the supplied heating medium. As a consequence, power is generated. The heating medium discharged from the turbine is supplied to the condenser. The condenser liquefies the heating medium, and supplies the liquefied heating medium to the heat exchanger again.
The foregoing turbine generator includes: a rotor having rotary shafts on its two sides, respectively; a stator disposed surrounding the outer periphery of the rotor; the turbine mounted on one of the rotary shafts; a housing configured to house the rotor and the stator in its internal space; and a bearing device installed in the housing, and including a first bearing rotatably supporting one of the rotary shafts, and a second bearing rotatably supporting the other rotary shaft. A first vent hole to eliminate a pressure difference between the turbine and rotor sides of the first bearing is drilled in the housing. Furthermore, a second vent hole to eliminate a pressure difference between the rotor and counter-rotor sides of the second bearing is drilled in the housing. The first and second vent holes extend in directions inclined from the axial direction of the bearing device, respectively.
Since the first vent hole is formed, the turbine and rotor sides of the first bearing communicate with each other, and no pressure difference accordingly occurs between them. In other words, the pressure on the turbine side of the first bearing does not become higher than the pressure on the rotor side of the first bearing. This avoids leakage and resultant dispersion of grease contained inside the first bearing, and makes the first bearing operate smoothly. Moreover, since the second vent hole is formed, the rotor and counter-rotor sides of the second bearing communicate with each other, and no pressure difference accordingly occurs between them. In other words, the pressure on the rotor side of the second bearing does not become higher than the pressure on the counter-rotor side of the second bearing. This avoids leakage and resultant dispersion of grease contained inside the second bearing, and makes the second bearing operate smoothly.
It should be noted that a technology related to the foregoing turbine generator has been described in Japanese Patent Application Laid-Open Publication No. 2010-242551 (JP 2010-242551 A).